This program project grant will carry out interdisciplinary investigations of major cancers with important tobacco- or nutrition-related risk factors. Related interview-based epidemiological studies and "metabolic epidemiological" studies will be performed, the latter referring to the measurement of biochemical parameters in selected human populations. With regard to tobacco-related cancers, data obtained in studying the effect of low-tar cigarettes on risks of lung and other cancers will also permit examining the associations of passive inhalation and lung cancer, mouthwash use and oral cavity cancer, obesity and artificial sweeteners and kidney cancer, and coffee consumption and pancreas cancer. Biochemical studies will be carried out to learn more about smokers who switch to low-tar and nicotine cigarettes and compensate by smoking more heavily, and whether there are biochemical markers for cancer risk in oral cavity tissues of smokers who drink. Nutritional epidemiological studies will examine dietary factors in gastrointestinal and breast cancers, including overnutrition as a risk in breast cancer survival. These data will also be used to investigate hair dyes and oral contraceptives as risk factors for breast cancer. Biochemical studies will seek data on how diet affects the concentrations of hormones and lipids in the breast fluid of non-lactating women, and details on how diet affects bile acid metabolites which have been related to colon cancer. Populations from more than eight U.S. cities, Finland, Yugoslavia, and Japan will be studied.